Monday, May 9, 2011

MEXICO CITY — In the two decades that Carlos Slim Helú has turned a crumbling Mexican phone monopoly into a continental telecom giant, he has successfully fought off competitors and challenged authorities who wanted to limit his companies’ control.

But over the last few weeks, a series of developments is threatening to chip away at Mr. Slim’s dominance.
First, Mexico’s antitrust agency imposed a $1 billion fine on the wireless company Telcel, the local unit of Mr. Slim’s pan-Latin company América Móvil. Then, at the end of last month, the Mexican congress approved a tough new antimonopoly law that raises fines for monopolistic practices and permits prison terms for executives who have been found to engage in them.

Last week, a Supreme Court ruling halted a legal maneuver that Mr. Slim’s companies had used to fight lower tariffs. The decision gives new heft to the country’s telecom regulator as it begins to slash the high interconnection fees that América Móvil charges other companies.